Computed tomography of lymph node metastasis before and after radiation therapy: Correlations with residual tumour

Abstract

Background: Computed tomography (CT) performed after radiation therapy (RT) is used to detect residual lymph node (LN) metastasis. Here, we investigated which LN parameters on pre- and post-RT CT images correlated with residual tumour in patients with head and neck cancer. Patients and Methods: We enrolled 23 patients who received RT. A total of 50 LNs were evaluated. Correlations between quantitative and qualitative findings and residual tumours were evaluated. Results: The median patient age was 61 years. Thirty-one LNs were histologically confirmed to contain residual tumour. LNs with residual tumour had significantly longer short and long axes on post- RT CT images. A new finding of obscured margins after RT were significantly associated with the presence of residual tumour by univariate and multivariate analyses. Conclusion: Comparison of qualitative, LN parameters on pre- and post- RT CT images may improve the detection of residual tumour in patients with suspected residual or recurrent LN metastasis.